This two-phase project evaluates the relationship between sociodemographic, psychosocial, cognitive, and drug use variables and HIV infection in drug abusers, and the influence of HIV infection on drug abuse treatment compliance and outcome. The first phase involves retrospective analysis of data already collected on ARC subjects, using two analytic approaches: 1) case-control comparisons of subjects HIV antibody positive or negative who are matched on appropriate variables and 2) multivariate analyses using the entire sample of subjects to determine variables associated with HIV infection and treatment HIV infection high-risk behaviors and attitudes using self-report questionnaires and structured interviews. Data is collected from ARC treatment research subjects at treatment entry and again at follow-up in order to evaluate possible changes due to drug abuse treatment or drug abstinence. Initial analysis of retrospective case-control data from 22 HIV-antibody positive, physically asymptomatic cocaine addicts and 22 matched HIV seronegative cocaine addicts indicated that seropositive subjects were significantly more likely to be HIV cocaine users. Otherwise, there were no significant differences between the two groups in sociodemographic, psychosocial, cognitive, or treatment compliance variables.